1. Field of the Invention
The present invention relates to compressors that may preferably be used in automotive air conditioning systems and other devices.
2. Description of Related Art
As one type of known compressors, a variable displacement compressor is disclosed in U.S. Pat. No. 5,873,704 and is typically used in automotive air conditioning systems. The variable displacement compressor changes the compressor output discharge capacity by changing the pressure within a crank chamber that includes a swash plate. The swash plate is coupled to a drive shaft and rotates together with the drive shaft. The swash plate changes the inclination angle with respect to the plane perpendicular to the axis of the drive shaft. A cylinder block includes a valve plate that covers the cylinder bore and a rear housing is disposed on the rear side of the cylinder block. The rear housing contains a suction chamber and a discharge chamber for the refrigerant. The valve plate and the rear housing are fastened to the cylinder block by a gasket and fastening bolts attached to the adjoining surfaces.
Because known compressors require the valve plate and a plurality of gaskets on the rear side of the cylinder block, a large number of parts are required and the manufacturing cost is naturally influenced by this requirement. Moreover, the cylinder bore sometimes deforms due to the fastening force applied to the fastening bolts when the valve plate and rear housing are fastened to the cylinder block using the fastening bolts.
It is, therefore, an object of the present invention to provide improved compressors.
In one aspect of the present teachings, compressors are taught that minimize the number of parts in view of known compressors. By minimizing the number of parts, manufacturing costs can be reduced.
In another aspect of the present teachings, compressors include a piston disposed within a cylinder bore. A wall seals the cylinder bore and is integrally formed with the cylinder block. That is, the wall preferably extends substantially perpendicularly from a side portion of the cylinder block without a seam. Further, the wall may function as a valve plate and thus it is not necessary to prepare an additional valve plate that is separate from the cylinder block. Because the need for a separate valve plate can be eliminated in this embodiment, the number of gaskets can be reduced. Consequently, the number of compressor parts can be reduced compared to known compressors and manufacturing costs can therefore be reduced in this embodiment.
In another aspect of the present teachings, a suction valve and/or a discharge valve may be disposed within the wall. Thus, this embodiment provides a simple configuration for the location of the suction and/or discharge mechanisms. The suction valve and/or the discharge valve may have a large port diameter and a large degree of valve lift. As a result, refrigerant pressure loss during the suction and/or the discharge operations is minimized and an efficient compressor may be realized.
A suction chamber and/or a discharge chamber may be disposed between the wall of the cylinder block and a rear member that seals the rear side of the cylinder block.
For example, a portion may extend toward the rear side of the wall and the adjoining surface of the portion and the rear member may be positioned as far as possible from the cylinder bore. In this case, detrimental effects of the fastening force are prevented from deforming the cylinder bore when the rear member is fastened to the portion of the cylinder block with a fastening bolt. Therefore, refrigerant leakage from such deformation can be prevented and an efficient compressor can be realized in this embodiment as well.
By extending the cylinder block to the rear side of the wall, the suction chamber and/or the discharge chamber can be disposed on the rear side of the wall. Further, the rear member that seals the suction chamber can be fastened to the discharge chamber in a plate-like manner. Consequently, the shape of the rear member can be simplified.
Additional objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims. Because this summary does not describe all features of the present teachings, sub-combinations of the features described below may be utilized to realize other aspect of the present teachings.